Chromo-chromic Oxides

Two hydrated oxides, Cr₃O₄.H₂O and 2Cr₃O₄.4H₂O, are said to exist, the former being described by Peligot as a product of the action of heat on chromous hydroxide, while the latter is obtained as a yellowish-brown powder with vigorous reducing properties, stable in dry air, but decomposed on heating, by the decomposition of the double chromous potassium carbonate with boiling water in absence of air. The existence of an oxide, of composition 2CrO.CrO₃ or 3CrO.CrO₃ described by Bunsen, has not been confirmed.